If you had any doubts that the Republican Establishment was fighting a no-holds-barred civil war against grass-roots conservatives and the Tea Party, wonder no more.

This weekend, House Speaker John Boehner reportedly will attend a $5,000-a-head Amelia Island, Fla., event. It’s sponsored by the anti-tea party group Republican Main Street Partnership and heavily funded by labor unions. Boehner’s No. 2 guy in the Republican House, Eric Cantor, will also be in attendance along with 25 other Republican Congressmen.

If you wonder why GOP opposition to President Obama’s policies is so weak, look no further than the not-so-dynamic duo of Boehner and Cantor. Neither one of them would have gotten their positions of power if it wasn’t for the strong support of Tea Party Republicans in the 2010 midterm election. But they seem to have forgotten that and have a strong dislike for Tea Party supporters who helped them take the House.

Steve LaTourette, a liberal Republican former Congressman from Ohio, is the face of the Republican Main Street Partnership and good friends with John Boehner. The group claims to be conservative and to support Republicans, but in reality it does just the opposite. LaTourette himself has a long history of attacking and trying to defeat conservatives.

Although it has “Main Street” in its name, it’s as far from an American Main Street in location and ideology as you can get. LaTourette’s group has received money from left-leaning unions, George Soros-backed organizations, and a major Democrat contributor.

The Mainstreet Partnership has multiple offshoots all housed on the 6th floor of a 7th Street office in Washington, D.C. Together, the groups — including Main Street Advocacy — want to, in the words of their backers, “bolster our incumbents who are under attack from the far right, and ensure that we hold on to seats represented by pragmatic Republicans that we would otherwise lose if there was an ultra-conservative in the general runoff.”

Another example is the Club for Growth. This is an organization that once challenged Establishment Republicans in primaries with its previous support of Joe Miller in Alaska. Miller is considered one of the best Tea Party candidates in the country, and is seeking an Alaskan Senate seat this year. But today the Club for Growth is working with these insider candidates; backing Senate Minority Leader Mitch McConnell in Kentucky, and Alaska Senate candidate Dan Sullivan.

If you have any doubts about the members of the Mainstreet PAC, here’s the list which includes two of the biggest Senate insiders, Susan Collins of Maine and John McCain of Arizona.

Given the level of anger and frustration throughout the country, this year’s election should be one of the most intense political battles in American history. Only time will tell if Establishment power and money or Tea Party principles will prevail.